Involuntary Muscles or Unstriated Muscles

Involuntary Muscles Definition

Involuntary muscles are those that move or operate without conscious control. They are under the control of the automatic nervous system but not under the control of the will. They are the part of a large internal organ of the body that functions regularly. The stomach is an example of an involuntary muscle, it does its function but the body does not have any control.

There are a lot of different types of muscle tissue, and if you haven’t already read about them, you should. It will only take a few minutes, but you will have a better idea of unstriated Muscles then. Since there is no presence of cross striations or light and dark bands so Involuntary muscles are also known by Unstriped Tissue.

The Involuntary muscles or Unstriated Muscles are small in size about 0.02 to 0.05 mm in length and 8 to 10 pm in diameter. These are spindles and both the ends are pointed. Each muscle fibre is externally covered by a plasma membrane and not by sarcolemma. It is uninucleate with a single, oval and centric nucleus. The myosin is formed by the random arrangement of myosin and actin filaments. These are usually arranged in layers forming sheets in the wall of visceral organs. These are less vascular. Smooth muscle or ” involuntary muscle” is found within the walls of organs and structures such as the oesophagus, stomach, intestines, bronchi, uterus, ureters, bladder, and blood vessels. Unlike skeletal muscle, smooth muscle is not under conscious control.

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What are Visceral Muscles

The muscles are found in the wall of hollow organs such as the alimentary canal, blood vessels, respiratory passage, unitary bladder, and genital tract. Thus are also called visceral muscles. That means unstriated, involuntary, and visceral muscles are the same but named according to their location and types.

The smooth muscle sustains longer or even near-permanent contractions without undergoing fatigue. In contrast, with striated muscles, smooth muscle occurs at various scales in almost every organ, from the skin ( in which it controls the erection of body hair) to the blood vessels and digestive tract ( in which it controls the caliber of a lumen and peristalsis).

Properties Of Involuntary Muscles ( Unstriated Muscles )

1. These muscles are spindle-shaped tapering at both ends with numerious fine longitudinal myofibrils.
2. Each myofibril contains a single oval nucleus at the middle. There is no sarrcolemma.
3. The fbibre being bounded merely by its plasma membrane.
4. The cross striations or light and dark bands are absent. Helce muscles are smooth and unstriated or unstriped type.
5. The muscles are found in the wall fo hollow organs such as alimantary canal, blllo vessels, respiratory passwage, urinary bladder, and genital tract. THus they are also called visceral muscles.
6. They exhibit show but prolonged contraction. These muscles are not fatigued (tired).
7. They are under the control of autonomic nervous system but not under the control of will. Thus they are called as involuntary muscles.

Hence from this article, we learned that involuntary tissue is not in control or will. These organs function unconsciously and make the body stable. Involuntary tissue movement is the uncertain movement in the body organs it may be due to less oxygen in the brain, brain injury, or some side effects of drugs. This muscle is also named by some other terminology like Unstriated, Unstriped, and Visceral Muscles. This much for now, if you have any confusion related to this topic then feel free to comment down.

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